1. Field of the Invention
The present invention relates to an even-irrigation apparatus for an underground root zone and an even-irrigation method using the same, and more particularly, to an even-irrigation apparatus for an underground root zone and an even-irrigation method using the same, which can directly and evenly supply water to the root zone of a variety of crops, such as fruit trees, decorative plants, landscaping plants, etc.
2. Description of the Related Art
As is shown, there are a variety of irrigation methods including hose-irrigation, drip-irrigation, jet-irrigation, spray-irrigation, mist-irrigation, furrow-irrigation, underground-irrigation, etc.
Specifically, hose-irrigation is a method for supplying the ground surface with water using hoses. In drip-irrigation, a plastic pipe or tube is perforated with small-diameter holes, and capillary tubes connected to the holes are provided at tip ends thereof with nozzles or water outlets, from which water droplets are dropped in small amounts. Jet-irrigation is a method in which water is ejected from tubes perforated with holes, spray-irrigation is a method for spraying water using nozzles, and mist-irrigation is a method using a mist generator for changing water into ultra-fine globules of water. Also, furrow-irrigation is a method for supplying water into furrows included in facilities, and underground-irrigation is a method for directly supplying water to roots of crops using irrigation pipes embedded underground.
All the above-mentioned irrigation methods, except for the underground-irrigation, are used to supply the earth surface with water and cannot directly supply water to roots of crops, causing excessive consumption of water due to evaporation and consequently, increasing the usage of agricultural water. For this reason, the underground-irrigation has been widely employed. For example, Korean Patent Publication No. 1987-6 (entitled “Automatic Water Supply Device”, hereinafter referred to as “cited invention 1”) discloses a water supply device based on underground-irrigation. The disclosed water supply device is illustrated in FIG. 1.
As shown in FIG. 1, the automatic water supply device 100 includes a water reservoir 101, a water supply head 102, and a water supply pipe 106. The water reservoir 101 has a water level lower than a position at which the water supply head 102 is inserted into the soil of a pot. The water supply pipe 106 is connected between a lower interior position of the water reservoir 101 and the water supply head 102. The water supply head 102 includes a tubular water supply portion 103, which is made of a water-permeable material and has a closed conical lower end, the tubular water supply portion 103 being inserted into the soil, a head portion 104, which is made of a waterproof material and is connected to an upper open end of the tubular water supply portion 103, and a water outlet 105 through which water, having passed through the water supply pipe 106, is directed into the head portion 104 of the water supply head 102.
The above-described conventional automatic water supply device is designed to continuously supply water on the basis of a pressure difference caused depending on the content of moisture in the pot, more particularly, the germination pot. Evaporation of moisture supplied into the germination pot causes a reduction in the interior pressure of the pot. With the resulting pressure difference, water stored in the water reservoir is drawn into the germination pot. Although this continuous automatic supply of water in response to the evaporation of moisture is advantageous in view of the maintenance of an appropriate amount of moisture, it cannot be said that maintaining the optimal constant content of moisture is essentially beneficial to cultivation of field products, such as vegetables, or fruit trees. As occasion demands, it may be necessary to supply water in proportion to the photosynthesis of a plant, or to control a low content of moisture. Therefore, in fact, the above-described automatic water supply device cannot be appropriately used because adjusting the supply amount of water and the supply position of water in the soil in consideration of growing conditions of a plant is advantageous to achieve improved productivity of the plant with reduced consumption of water.
Furthermore, the above-described conventional automatic water supply device is costly equipment. In an agricultural cultivation environment wherein water must be supplied to a great amount of crops, such as fruit trees, decorative plants, etc., distributed over a wide area, it is difficult to install a plurality of such costly equipment. For this reason, the use of the automatic water supply device is limited only to laboratories for measuring the content of moisture in soil, nutrient-solution cultivation greenhouses, etc.
To solve the above-described problem, the applicant of the present invention has proposed Korean Patent Registration No. 556300 (entitled “Underground Irrigation System”, hereinafter referred to as “cited invention 2”). In the disclosed underground irrigation system, as shown in FIGS. 2 and 3, water is directly supplied to roots of a plant from a position optimally selected in consideration of the growth of roots of the plant, for assuring effective rooting of the plant, effective adsorption only to the roots of the plant and consequently, facilitating the growth of the plant. The conventional underground irrigation system includes a water reservoir 201 in which water is stored, a pumping device 203 to pump the water stored in the water reservoir 201 by a set pressure, and an irrigator device 210 installed adjacent to a plant. The irrigator device 210 includes a head portion 211, a body portion 216 and a tip portion 221. The head portion 211 is laterally formed with an inlet 213, into which the water pumped by the pumping device 203 is introduced, and a water tube 214 is received in the head portion 201 so as to extend vertically from the lateral inlet 213. Further, a hitting portion 215 is formed at the top of the head portion 211. The body portion 216, which is coupled to the bottom of the head portion 211, internally defines a center passage 217 in communication with the water tube 214, and an outlet 219 in communication with the passage 217 is formed at a lower end of the body portion 216, to discharge the water to the outside. The tip portion 221 is coupled to the bottom of the body portion 216 and is conically tapered to assure easy insertion thereof into the ground. The body portion 216 is externally provided with a scale 220, to assist a user in insertion of the irrigator device 210 to an optimal depth underground, so as to supply water at an optimal position depending on the growth of roots of the plant. The center passage 217 of the body portion 216 is combined with a delay passage 218, which serves to delay the flow rate of water passing through the center passage 217 while increasing the temperature of water.
The above-described cited invention 2 has an advantage in that it can facilitate the growth of crops by allowing roots of crops to be rapidly spread downward, thereby enabling early harvesting of crops while preventing cold-weather damage of shallow roots, resulting in an increase in profitability. Further, by virtue of reduced evaporation of moisture, the cited invention 2 can restrict dew condensation at facility houses and minimize disease damage to crops. Furthermore, supplying water into a deeper underground region can prevent the ground surface from being muddy, increasing workability with respect to harvesting, disaster measures, transportation of handcarts, etc., and remarkably reduce the usage of agricultural water, resulting in reduced consumption of water resources and increased growth effects.
As another solution, the applicant of the present invention has proposed Korean Patent Registration No. 594479 (entitled by “Underground Irrigation System”, hereinafter referred to as “cited invention 3”) as shown in FIGS. 4 and 5.
As shown, the underground irrigation system disclosed in cited invention 3 includes a water reservoir 301 in which water is stored, a pumping device 303 to pump the water stored in the water reservoir 301, and a plurality of irrigator devices 310, each of which includes a tubular body 316 to supply the water, pumped by the pumping device 303, into the ground, the tubular body 316 being provided at opposite ends thereof with an inlet 314 and an outlet 319. A pressure control valve 302 having a knob is installed at one side of the electric pumping device 303. Nipples 305 are provided at respective junction positions of a pipe, which connect the pumping device 303 and the respective irrigator devices 310 to each other. A reducer 307 having a pressure-reduction hole 308 is inserted into a center hole 306 of each nipple 305.
All the above-described cited inventions wherein a single irrigator device is used to supply water to a single position commonly have a problem in that roots of a plant are inclined toward the irrigator device according to the passage of time, making it difficult to assure balanced growth of the plant. Moreover, although it is necessary to concentrate a desired amount of water required for the growth of a plant on a specific underground position, the above-described conventional irrigator devices provide only radial permeation of water, causing evaporation of about 50% of water supplied, or causing water to be adsorbed into irrelevant soil distant from a root zone. This requires supplying double the water that is actually adsorbed to crops and results in waste of water resources.